Method of making auger bits



Oct- 13, 1925- L'. S. WHITNEY Filed Nov. 11, 1924 1-;,LUNITED ST Patented Oct. 13, 1925.

PAT ENT OF ICE 'LA'RNED swarm, or rIsxnALE,mnssncnusntrrsd METHOD-or MAKING AUGE'IR ni'r's.

Application filed November 1, 1924. serm in. 749,114.

To all whomz't may concern:

, Be it known that I, LARNED S. WHITNEY, a citizen of theUnitedStates, residing in Fiskdale,jin the county of Worcester and State of. Massachusetts, have invented certain new and useful Improvements in Methods of Making Auger Bits, of which the fol lowing is a specification.

The invention relates to a method of making auger bits.

The more commonly practised method of producing auger bits at the present time is by forging with trip-hammers and drophammers. According to this method a relatively short piece ofjsteel is heated and then subjected to a seriesof forging-dies by which it ishammered into a bit blank in condition for machining. After the forging operation it is necessary to ascertain whether the bit blank is free from fire cracks, forging defects, and whether it is.

of proper length and size. The bit blank isthen subjected to a series. of machining operations by which the spurs, lips and lead screw are out and the bit ground and- 01- ished. Forged bits vary considerably in length, diameter and general condition, so

much so in fact that it'is often impracticable to employ jigs or other fixtures for performingthe operations of cutting the lips, spurs and lead screw. Consequently, these operations must often be performedentirely by hand, thereby greatly increasing the'cost of producing the bit. Moreover,forged bits are often defective in that the shank and spiral are not concentric with the lead screw and spurs, so that the bit does not run true when it 'is, put in the brace 01' bit-stock.

Such is the percentage of imperfect auger bits v produced by the present method of .forging that the bits returned to the fac- "tories by the'trade because of various kinds of defects is a source of serious loss to the manufacturers.

Theobject' of the present invention is to produce a method of manufacturing auger bits by which the bits will be more uniform '5 ly accurate in length and diameter, will be struction to forged'bits. u 'is produced entirely, by a series of machine free from fire'and'forging defects, and will be superior in general c'onditionand con operations from a rod or bar of stock of the requisite size, usually slightly larger in diameter than the finished bit. By making the'bits from a round bar by a series of opvthereby greatly reducing the ing the finished bit.

To this end the bit is cut on the end which is to be inserted in erations performed on diiferent machines, some of the operations being entirely automatic, the bit blanks producedb the first ofrthe series of operations will e'so uniform in size and eneral conditionthat'the subsequent operatlonsof cutting the spurs,

lips and lead screw, may all be accom lished in jigs or other fixtures. Moreover, y machining all theparts of the bit, such as the spiral, the shank and the nib or tang, which have formerly been fashioned by forging,

the operation of grinding and polishing the bit is more quickly and easily performed,

cost of produca perspective view of a bar of stock from which the bit is produced; Fi 2 shows the bar after the forward end has een operated on to blank out the parts for the spurs, lips and lead screw, and the t ang'has been cut on the other "end; Fi 3 shows the blank with. the shank turne down'thereon; Fig.

4 shows'the blank after the spiral has. been cut; and Fig. 5 isa viewof the finished bit. In producing an augerbit according to the method of the resent invention, a bar of round stock sli tly larger indiameter than the finished itis first/placed in a lathe'and the end projecting from-thechuck 'is countersunk, as shown at 7 in Fig. 2, so as to. form theannulus 8 and thecone 9 from which the spurs 1'0 and lead screw 11 (Fig. 5) are made. Preferably an automatic turret" lathe is used and the bar of round stock ,is of such length that several bit blanks may "cutfso'as not to subject the relatively slen- ,der shank portion to the'stresses incident to the cutting of the tang; 1

The bit blank having been cut to length in the turret lathe is next placed in a mill- The accompanylng drawings illustrate the various steps in producing auger bits by the 'method of the present invention :Fig. 1 is ingmachine and the tapered tang or nib 12 p the brace or bit-stock. The bit blank now exists as shown in Fig, 2. The shank portion 14,(Fig. 3) is next turned down in a lathe, after which the body portion 151s produced by the: forging processes.

1 greater the formin turned to size, leaving just enough stock for the grinding and polishing operations after the spiral 17 (Fig. 4) has been cut.

The bit blank 16, 'Which now e'Xists as shown in Fig. 8, is then placed in a machine by which the stock between the wv'alls 17 forming the spiral is removed. This operation is preferably performed by "oppositelydisposed cutters in a milling machine, one such inachine forming the subject-matter of my bofpending application, 'Serial No. 7 49,-

1115, filed November '11, 1924. it will be ,"noted 'that the cutters which cut the spiral begin the milling operation at the .point 18 where the body part 15 ofthe bit j oins With the shank 1 4: and proceedo'nly as far as the bottomQQoithe countersunk recess 7, so'as to leave sufficient stockirom ivhich the spurs of the bittaper trom the point 18 toward the point23, the middle of the bit yvh'erethe stresses come is strengthened. Moreover, by tapering the center stem of the spiralportionofthebit the operative is enabled to properly cut'the spiral Without sinking the cutters into the shank.

All the foregoing operations, including of thetang and thecutting of the spiral, having been performed on abar ot stockpthe'diameter or Whichis substantiallythe same throughout its length, the bit blilllklShOWVIl *in'Fig. '4 is such condition that the subsequent operations of cutting and finishing "the spurs, lips or cutting edges, and the lead screw, be all performed by machine While the bit blank is held in a "jig; or other fixture. Thus these operations will be uniformlyperformed and theparts otall the bits producedby'them will be-uniform insize. The bits are now ready for hardening, tempering, grinding,

polishing and "sharpening, allot which operations areIperfOrmedin-the usual manner.

The shank-1d and spiral 17 having been cut by machine, it Will be obvious that-the "operations of grinding and ;-polis hing these parts are more easily and quickly effected than When the bitis forged.

The finished bits (Fig 5) produced by practising therpresent method are accurate :as to size, concentric throughout their length, are free 'from fire defects or other detectsvincident to forging, and *allthe bits of a given size are uniform. Thus the auger bit for carpenter use which has heretotore been a tool of uncertain. size and accuracy, has been by the present invention converted into a tool of precision.

Having thus described the invention, What I claim as new is 1. The method of making auger bits from a bar of round stock, which consists in the following steps taken in substantially the given order: turning on the end of the bar the part for the lead screw and'spurs, cutting from "the bar alength'equal to "the fin ished bit, forming the tan mrniagnown the shank, milling the spiral "slot, cutting the lips and spins, and "threading the screw.

'2. The method of 7 making "auger bits, which consists in turnii'i'g the 'point and shank portions on "a lathe, cutting thetafng on a milling machine, cuttingftlie 'spiral'slot on another machine, and then torming the spurs and lips and threading "the point.

3. The method of l naking' auger'bits'from a bar of round stock of substantially the same 'size as the finished bit, which consists in countersinkin'g one'end of the 'bar ffolr the lead screWfand the spurs, icuttin'g off from thebar apiece the length ot'thefinishfe d bit,

forming the tang, turning down -a portion of the 'bar to fo'rm'the shank, cutting the spiral 'slot,'fo'rniing the'spujrs and lips, ciitting the lead screwyand'gri nding and'polishing. V I

4. The methodot r'nakin'g" auge1'"bi-ts from a. bar of round'stock,which 'consi'sts-in'tu'rning the parts for thespu'rs, lead screw and "shank, forming the 'tang,1nillinjg"thespiral slot,'cuttin'g the lips, and finishing-the spam and lead screw. p i

'5. The method of making augei-bits'fmm a bar of round stock ofsubstantiallyfthe same size and length "asQthe "finished "bit,

which consists in machining the st'oekto "form the lead screw, the sp urs,"'the' lips, the tang,an d theshank, milling the "spir'a-Pslo-t, and then grinding and polishing the bit,

' 6. The method of in'aking auger"bits"itrom a bar of round stock of substantially the same size; and length as the finishethbit, which consists in machining the stock "to form the lead screw, the spurs, the lips, "the tang, and the sh ank, cutting the spiral slot 'so t hat'the c-enterste'm or eqre thered'f will taper froin'thep'oint where thejspir'alijoin's theshank toward the cuttingend oifthe loit, and thengriudin and polishingthe bit.

'7. The method of making i auger bits froin a bar of round's'tock, Which-consists inturning the parts "for the spurs, lead screw fand shank, forming the tang, "milling the spiral slot so that'the cent'erstem ouc'o rejof the spiral willhave a taper from the inid'dl'efof {the bit toward the cutting end thereof, cutting the 'lips, and --finishing"thesp'ur's and lead'screw. LARNED S. 

